Process for treating petroleum coke



United States Patent 3,322,550 PROCESS FOR TREATING PETROLEUM COKE Richard M. Murphy, 359 Mansfield Ave., Darien, Conn. 06820 No Drawing. Filed June 11, 1965, Ser. No. 463,388 11 Claims. (Cl. 106-56) This is a continuation-in-part of application Ser. No. 218,449 filed Aug. 21, 1962, and entitled, Process for Treating Fluid Petroleum Coke, now abandoned.

The present invention relates generally to the treatment of petroleum coke, and in particular to a process for the preparation of compacts of petroleum coke and an agglutinating carbonaceous binder. The resultant compacts, after tempering and in most cases after subsequent calcining or coking, which may be in the form of pellets, extrusions, briquettes, cylinders, structural blocks and the like, have the requisite physical and mechanical properties to be useful in a wide variety of applications, particularly coke for metallurgical and chemical processes and the like, but also including, Without limitation, carbon shapes such as blocks, bricks and tiles for architectural and other purposes.

The tWo most common forms of petroleum coke are delayed coker process coke and fluid coking process coke. The delayed coking process is 'well known and has been widely used in the petroleum refining industry for more than thirty years. Delayed coke is deposited on the interior walls of vessels, known as coke drums, in the form of raw or green petroleum coke. For most industrial uses, green petroleum coke is devolatilized by cal-" cining. Calcined delayed coker coke is not mechanically strong enough for many metallurgical and other applications.

Fluid coke is prepared by a recently developed continuous heat-balance fluidized-solid process involving the thermal conversion of heavy hydrocarbon oils to lighter fractions. Fresh feed, usually a heavy r'esidium, is dispersed into a fluidized coke bed which may be operated within the range of 900 F. to 1,000 F. The thermal conversion products, including gas and a full-boilingrange distillate, leave the reactor as overhead vapors. A portion of the charged stock is converted to coke, which is deposited on the fluidized coke particles already in the reaction zone. Heat balance is accomplished by circulating coke between the reactor and the burner where a portion of the gross coke make is burned with blower air to supply pre-heat and heat of reaction. The net coke is withdrawn as a product through an elutriator which returns fines to the burner.

A typical fluid-coking unit includes a reaction vessel or coker and a heater or burner vessel. The heavy oil to be processed is injected into the reaction vessel containing a dense, turbulent fluidized bed of hot inert solid particles, preferably coke particles. A transfer line with stage reactors can be employed. Uniform temperature exists in the coking bed and mixing in the bed results in virtually isothermal conditions and effects instantaneous distribution of the feed stock. In the reaction zone, the feed stock is partially vaporized and partially cracked. Product vapors are removed from the coking vessel and sent to a fractionator for the recovery of gas and light distill-ates therefrom. Any heavy bottoms are usually returned to the coking vessel, while the coke produced in the process remains in effect coated on the solid particles. Stripping steam is injected into the stripper to remove oil from the coke particles prior to the passage of the coke to the burner.

The heat for carrying out the endothermic coking reaction is generated in the burner vessel, usually but not necessarily separately. A stream of coke is thus transferred from the reactor to the burner vessel, such as by a transfer line of fluid bed burner, employing a standpipe and riser system; While air is supplied to the riser for conveying the solids to the burner. Sufficient coke or added carbonaceous material is burned in the burner vessel to bring the solids therein up to a temperature sufiicient to maintain the system in heat balance. The burner solids are maintained at a higher temperature than the solids in the reactor. About six percent of the coke, based upon the feed, is burned for this purpose which may amount to approximately fifteen to thirty percent of the coke made in the process. The net coke production, which represents the coke made less the coke burned, is withdrawn.

Heavy hydrocarbon oil feed suitable for the coking process include heavy crudes, atmospheric and crude vacuum bottoms, pitch, asphalt, and other heavy hydrocarbon petroleum residue or mixtures thereof. Typically such feeds can have an initial boiling point of about 700 F. or higher, an A.rP.I. gravity of about 0 to 20, and a Conradson carbon residue content of about 5 to 40 Wt. percent.

Petroleum coke is available from other and lesser known sources, such as continuous contact coke generated by the so-called Lummus process or the Hoechst process. A still further source of petroleum coke is derived from sole heated ovens, such as the Knowles oven having a silicon carbide floor.

It is also generally known how to compact petroleum coke, which is relatively non-porous, into various shapes, such as pellets, extrusions, briquettes, cylindersvand the like by utilizing an agglutinating carbonaceous substance as a binder. Suitable binders include asphalt and other heavy petroleum residues, aromatic tars, heavy ends of coal tars such as coal tar pitch, having a minimum softening point of about C. and heavy ends from the coking operation. Some specific examples of suitable binders which may be obtained commercially are Elk Basin residium F. softening point), Enjay 160 asphalt and Hawkings coker bottoms. These substances may be utilized in amounts of approximately five to twenty percent by weight based upon the coke charge and preferably within the range of eight to fifteen percent by weight. However, it has been found that these compacts have very limited uses due to the practical inability to produce shapes having substantial strength (i.e. sufficient- 1y strong to elficiently replace coal coke in metallurgical and other processes, especially in those that require high temperature crushing resistance) combined with the desired density characteristics.

The present invention is based upon the discovery that compacts with suflicient strength and optimal density or porosity properties to render them suitable for a Wide variety of purposes can be prepared from petroleum coke and an agglutinating carbonaceous binder by first providing the petroleum coke particles with activated exterior surfaces and mixing such activated coke with the agglutinating carbonaceous binder, after which the mixture is compacted and tempered in either order and then ooked. It has been unexpectedly found that the employment of activated petroleum coke enables the production of finished products having a crushing strength Well in excess of 1500 pounds per square inch, as compared to products which are prepared from tin-activated petroleum coke wherein it is difficult to produce a crushing strength even approaching 1000 pounds per square inch. When compacting and tempering, or compacted, tempered, are both recited in any claim herein, it will be understood that the claim covers carrying out these compacting and tempering steps in either order.

Further, the products of this invention have highly desirable density or porosity characteristics whereby they are peculiarly and advantageously adapted for use as a combustible fuel, particularly as an improved metallurgical coke in smelting, melting and other metallurgical operations. Whereas conventional metallurgical coal coke, the standard fuel for commercial blast and foundry cupolas today, rarely has a real (or apparent) density of more than 1 gram per cubic centimeter (gm/emf), the products of this invention have real densities ranging from about 1.05 to 1.35, and usually about 1.10 to 1.30 gm./ cm. Such relatively higher densities (i.e. more concentrated fuel) have the highly desirable effect of increasing the capacity of blast furnaces, cupolas and similar combustion facilities, and are surprising in view of the immediate density-reducing or porosity-increasing effects of the initial activating step required herein. Coke with a still higher density of more than about 1.35 (a porosity of less than 33%) would not however be suitable for the desired purposes since it does not have sufiicient porosity to support the minimum rate of combustion essential for efficient smelting and melting in industrial metallurgical processes.

Numerous techniques are known and available for activating carbon. One practical step for providing the petroleum coke particles with an activated surface involves fluidization in an atmosphere of steam and air at a temperature in excess of 500 C. and for a period in excess of ten minutes. If delayed coker petroleum coke is to be employed, it should first be reduced size by screening, crushing or other means. I prefer the maximum size to be about inch, or of a size range commonly described as 14 mesh, US. Standard Sieve. The steam to air ratio may vary and will depend upon the activating temperature and time. It has been found that a mixture of seven-tyfive percent steam and twenty-five percent air is effective at 550 C. to activate the exterior surfaces of petroleum coke particles in a reasonably short period of time. Other techniques generally known for activating carbon and which increase the porosity thereof, find useful application herein in the activation of the exterior surfaces of petroleum coke particles, although such techniques have not been employed with the relatively dense and non-porous petroleum coke and for the express purpose of activating the exterior surfaces of particles thereof. Such techniques are described in the literature, including such publications as Active Carbon by John W. Hassler, published in 1951 by Chemical Publishing Company, Inc., of Brooklyn, New York.

While I prefer to activate the exterior surfaces of petroleum coke particles in a fluidized bed, many other techniques may be effectively employed including, without limitation, activation in a fixed bed, in a moving bed, in a vessel in which counter current flow is established, in a vessel in which concurrent flow is established, in a rotating drum or in any device in which the petroleum coke particles may be exposed to the activating atmosphere under proper conditions of time and temperature. Suitable activation may also be achieved in an atmosphere of air at a temperature in excess of 450 C. for periods exceeding 5 minutes.

It will be understood that no claim is here made to any activating procedure per se, but only when employed in the described combination of steps for achieving the desired improved compacts. The activating step operative herein is commonly referred to as a selective controlled oxidation of carbonized or carbonaceous material with suitable oxidizing gases at elevated temperatures for increasing the surface area, porosity and adsorptive capacity of such material, the success of which depends to a large degree on the skill and experience of the operator. Generally speaking, the activating step may entail treatment with steam, air, or any mixtures thereof for periods of about 5 minutes to 24 hours at temperatures of about 450- 1000 C. and preferably about 550-800 C., depending upon the material being treated and the quality and degree of activation desired. Instead of air, any other gaseous atmosphere containing reactable oxygen can of course be employed. As is well recognized, activation with air is an exothermic reaction and care must be taken to prevent the temperature from exceeding the abovementioned ranges with resultant calcination and/ or uncontrolled combustion instead of activation.

The term activated petroleum coke in the following text is intended to mean petroleum coke which has had the exterior surfaces of its constituent particles activated, generally in the manner described above.

The activated petroleum coke is then mixed with an agglutinating carbonaceous binder such as asphalt, coal tar, gilsonite, pitch or other like known hydrocarbon binders. The selection of the particular binder and manner of mixing are in nowise critical and will depend upon the available materials, and to some extent the desired physical properties and ultimate use of the particular compact. The binders are used in an amount of between ten and twenty-five percent by weight based upon the activated petroleum coke, with the preferred range of binder to petroleum coke being between fifteen and twenty percent by weight. Mixing is preferably accomplished at a temperature at least equal to that at which the viscosity of the particular binder employed is 100 Saybolt Furol seconds. The temperature at which I prefer to mix the activated petroleum coke and agglutinating carbonaceous binder varies with the nature of the particular binder employed. For example, when using asphalt, I prefer to mix at a temperature below the smoking point of this binder.

After thorough mixture of the activated petroleum coke and the agglutinating carbonaceous binder by generally known techniques, the resultant mixture may be compacted into the desired final shape, likewise by generally known techniques.

In most cases I prefer to compact the mixture of activated petroleum coke and agglutinating carbonaceous binder before tempering it, as hereinafter described. However, good strong products maybe coked from shapes compacted after the tempering step.

Compaction is accomplished at a temperature in excess of the ring and ball softening point of the binder. The temperature at which I prefer to compact the mixture varies with the nature of the binder. For example, when using Mobil -100 asphalt, I prefer to compact the mixture at a temperature between C. and 200 C.

Depending on time, temperature and the nature of the binder, compaction may be accomplished under pressures varying from about 10 p.s.i. to 24,000 p.s.i. I prefer to employ pressures in the range of from 500 p.s.i. to 3,000 p.s.i. for compacting mixtures of activated petroleum coke and agglutinating carbonaceous binders in cases where maximum crushing strength is desirable. In cases where greater density within the ranges referred to above is an important consideration, higher compaction pressures will result in a denser product.

Thereupon, the resulting compact is tempered or annealed in an atmosphere containing at least four percent by volume of oxygen. It is believed that after activation, the surfaces of the petroleum coke particles are largely occupied by adsorbed gases, primarily hydrogen. The annealing or tempering appears to break the adsorption bond to further expose the active surfaces of the carbon to bonding with the pyrobituminous molecules of the agglutinating carbonaceous binder, which bond survives subsequent calcining of the tempered compact into a mechanically strong coke having a homogeneous bond between the binder-derived carbon and the petroleum coke carbon.

In addition to elimination by evaporation of any relatively low boiling constituents that may be present in the binder, it is also believed that during tempering or annealing, oxygen converts some large molecules natively present in most agglutinating carbonaceous binders from molecules that are volatile at high temperatures to molecules that are pyrobituminous in character. The annealing or tempering in the presence of an oxygen atmosphere causes the consumption of oxygen and the production of water, which tends to support the theory that the surfaces of the activated carbon have hydrogen molecules bonded thereto preliminary to annealing or tempering. It should be appreciated that substantial and occasionally sufficient and equivalent tempering of the compressed binder-petroleum coke mixture will occur at ambient atmospheric temperatures and pressures if held for sufiiciently long periods but, as a practical matter, exposure to temperatures in the range of about 200 C. to 300 C. in an atmosphere containing at least four percent oxygen and for periods of approximately to 2 hours is preferred. A higher percentage of oxygen may be advantageously used up to the normal proportion present in air; but as the oxygen content is increased there may be a companion hazard of combustion, if the tempering system is such that volatiles ten-d to concentrate in the contained atmos phere of the vessel in which tempering is accomplished. The upper temperature limit at which effective tempering can be achieved is approximately 300 C. at which the maximum oxygen in the atmosphere should not exceed ten percent, for oxygen in excess thereof will often cause burning instead of tempering, if present for more than a few minutes at this relatively high temperature. Any atmosphere of inert gases admixed with the stated amounts of oxygen can be used.

The tempering time and/or temperature may be reduced by adding -a suitable oxidizing accelerator to the mixture preliminary to tempering. Manganese dioxide, sulfur, magnesium oxide and calcium oxide (quick lime) have been found to be effective accelerators. Quick lime is an effective accelerator when mixed with the "binder on the basis of one-half of one percent or more of the total mixed weight equivalent. Such quick lime is relatively inexpensive and the residue of lime which is left in the resultant product is not an undesirable impurity for most metallurgical and other processes that customarily use coal coke.

Before coking, and whether compacted or not, but after tempering, the product is uniquely useful for blending wit-h certain coals that are to be coked in coal-coking ovens such as slot ovens, beehive ovens and sole-heated ovens. For example:

1) When blended with a coal that has too high a swelling index for undiluted charging to slot ovens, this product modifies the swelling index of the blend.

(2) When blended with any coking coal, or with any blend of coals intended for coking, this product increases the apparent density of the resulting coke.

(3) When blended with a weakly coking coal, this product improves the strength of the resulting coke.

After the annealing or tempering, the compacted prodnot is carbonized or coked, for example, by heating to a temperature in the range of about 600 C. to 950 C. for a period of approximately ten minutes to one hour, more or less, depending on the size 'of the compacted mass. The product preliminary to coking is a fuel similar to coal in some ways. In addition to substantially devolatilizing the product, coking contributes materially to improvements in the mechanical strength, especially in the crushing strength. Products having a crushing resistance on the order of 7,500 p.s.i. are obtainable in accordance with the present invention.

One potential advantage of coke made by this invention is that, without reducing the strength of the final coke below industrial requirements, other reactants required by coke consuming processes may be incorporated or composited in it. For example, coke may be made by the method of this invention which incorporates up to 35 percent quick lime or 65 percent iron ore or proportionate combinations of both and at the same time which resists crushing at pressures in excess of 1,500 p.s.i.

In order to more fully understand the invention, there are set forth below several illustrative examples for the production of compacts in accordance with the present invention. For the sake of convenience, the fluidized pe- 6 troleum process coke used in many of these examples is referred to by the abbreviation flucoke. Unless otherwise indicated, as referred to herein and the appended claims, amounts and proportions of vapors and gases are by volume and of solids by weight.

Example I Approximately 156.5 grams of fiucoke obtained from the Tidewater Refinery in Delaware was activated in a fluidized bed activation chamber in an atmosphere of 25% atmospheric air and 75% steam and held at a bed temperature of approximately 550 C. for a period of 25 minutes. The activated flucoke was then extracted from the activation chamber and mixed with 27.6 grams of asphalt (Mobils 85/100 penetration) in a stainless steel container with a single blade high speed mixing tool at a temperature in excess of 120 C. and in a normal atmosphere. The admixed activated coke and binder was briquetted into a number of cylinders, each of approximately 20 grams and of an outside diameter of approximately 1 /8". The briquetting was accomplished with a conventional Carver Press at a compacting pressure of approximately 20,000 p.s.i.

One group of the cylinders was then tempered by placing the same in a heated oven under a 5% oxygen atmosphere at a tempering temperature of approximately 225 C. for a period of minutes. The tempered cylinders were then coked for a period of approximately fifteen minutes at a coking temperature in the range of 800 C. to 900 C. and the resulting cylinders were cooled in the heating vessel while still covered. After cooling, the resulting cylinders had an average crushing resistance, as tested in a Carver Press, in excess of 1,700 p.s.i.

A further group of the compacted cylinders was allowed to age at ambient temperature and atmosphere for a period of approximately five days and was then tempered and coked under the conditions stated above. The pre-aged cylinders had a crushing strength, as measured on the Carver Press, of approximately 5200 p.s.i.

Example 11 Approximately 172.6 grams of fiucoke (Tidewater) was activated in a fluidized bed activation chamber in an atmosphere of 20% atmospheric air and 80% steam and held at a bed temperature of approximately 700 C. for a period of 20 minutes. The activated flucoke was then extracted from the activation chamber and mixed with 31.5 grams of asphalt (Mobils penetration) and 2.03 grams of calcium oxide as an accelerator. Mixing was at a temperature in excess of C. and in a normal atmosphere.

The admixed activated coke, binder and accelerator was then tempered in a heated oven under a 5% oxygen atmosphere at a tempering temperature of approximately 225 C. for a period of 42 minutes.

The tempered mixture was then briquetted at a compacting pressure of approximately 1,000 p.s.i. and the briquettes were coked at an end temperature of approximately 940 C. for a period of 34 minutes. After cooling, the resulting briquettes had an average crushing resistance of 4,000 p.s.i.

Example III Approximately 160.3 grams of flucoke (Tidewater) was activated in a fluidized bed activation chamber in an atmosphere of 15% atmospheric air and 85% steam at a bed temperature of approximately 700 C. for a period of 21 minutes. The activated flucoke was then extracted from the activation chamber and mixed with 28.2 grams of asphalt (Mobils 85/ 100 penetration) and 1.9 grams of calcium oxide as an accelerator. Mixing was at a temperature in excess of 120 C. and in a normal atmosphere.

The admixed activated coke, binder, and accelerator was compacted into cylinders at a compacting pressure of approximately 1,000 p.s.i. The cylinders were then tempered by placing the same in a heated oven under a oxygen atmosphere at a tempering temperature of approximately 225 C. for a period of 80 minutes. The tempered cylinders were then coked for a period of approximately 42 minutes at a coking temperature reaching as high as 920 C. and the resulting cylinders were cooled in the heating vessel while still covered. After cooling, the resulting cylinders had an average crushing resistance in excess of 4,000 p.s.i.

Example IV Approximately 176.4 grams of flucoke (Tidewater) was activated in a fluidized bed activation chamber in an atmosphere of 30% atmospheric air and 70% steam and held at a bed temperature of approximately 700 C. for a period of 14 minutes. The activated flucoke was then extracted from the activation chamber and mixed with 31.2 grams of a high melting point asphalt (Texaco No. and 2.1 grams of calcium oxide as an accelerator. The mixing was accomplished at a temperature in excess of 170 C. in a normal atmosphere. Briquetting was then accomplished at a compacting pressure of approximately 1,000 p.s.i. This was followed by tempering at a temperature of 225 C. for a period of approximately 80 minutes and coking out at a temperature reaching 920 C. for 28 minutes. The cooled resultant briquettes had an average crushing resistance in excess of 2,500 p.s.i.

Example V Approximately 74 grams of crushed delayed petroleum coke (Union Oil Company) was activated in a fluidized bed activation chamber in an atmosphere of approximately 15% atmospheric air and 85% steam and held at a bed temperature of approximately 700 C. for a period of 19 minutes. The activated delayed petroleum coke was then extracted from the activation chamber and mixed with 13 grams of asphalt (Mobiles 85/100 penetration) and .87 grams of calcium oxide as an accelerator. The admixing was at a temperature in excess of 150 C. and in a normal atmosphere. The mixture was then briquetted at a compacting pressure of approximately 1,000 p.s.i. The briquettes were then tempered by placing the same in a heated oven under a 5% oxygen atmosphere at a tempering temperature of approximately 225 C. After cooling, the briquettes had an average crushing resistance in excess of 2,000 p.s.i. For the successful treatment, the delayed petroleum coke should be at least partially coked, preferably to the extent that may be designated as a carbon to hydrogen ratio of 300 carbon to no more than 1 hydrogen.

Example VI Approximately 172.4 grams of flucoke (Tidewater) was activated in a fluidized bed activation chamber in a steam atmosphere at a temperature in the range of 550 C. to 700 C. for a total period of 30 minutes, with the activation being at the upper temperature limit for approximately 8 minutes. The activated flucoke was then extracted from the activation chamber and mixed With 30.5 grams of asphalt (Mobils 85/100 penetration) at a temperature in excess of 140 C. and in a normal atmosphere. The admixed activated coke and binder was briquetted at a compacting pressure of approximately 1,000 p.s.i. The compacts were then tempered at a temperature of 225 C. for a period of approximatley 80 minutes and coked out at a temperature ranging from 225 C. to 900 C. for a period of approximately 26 minutes. The resulting compacts had a crushing resistance of approximately 3,450 p.s.i.

Example VII Approximately 155.6 grams of flucoke (Tidewater) was activated in a fluidized bed activation chamber in a steam atmosphere at a temperature in the range of 550 C. to 770 C. for an overall time of 29 minutes, with the activation being at the upper temperature limit for approximately 15 minutes. The activated flucoke was then extracted from the activation chamber and mixed with 27.3 grams of a low melting point asphalt and 1.84 grams of calcium oxide, the mixing occurring at a temperature in excess of 140 C. The mixture was then compacted at a compacting pressure of approximately 1,000 p.s.i. The compacts were then tempered at a temperature of 225 C. for approximately minutes and coked out at a temperature in the range of 225 C. to 920 C. for approximately 26 minutes. The resulting compacts had a crushing resistance of approximately 3,350 p.s.i.

Example VIII Approximately 179.9 grams of flucoke (Tidewater) was activated in a fluidized bed activation chamber fluidized with a normal air atmosphere at a temperature of approximately 550 C. for a period of 10 minutes. The activated flucoke was then extracted from the activation chamber and mixed with 31.8 grams of the low melting point asphalt at a temperature in excess of 150 C. and in a normal atmopshere. The admixed activated coke and binder was briquetted at a pressure of 1,000 p.s.i. The compacts were then tempered at a temperature of approximately 225 C. for approximately 80 minutes and then coked out at temperature in the range of 225 C. to 920 C. for a period of approximately 34 minutes. The resulting cooled compact had a crushing resistance of approximately 3,150 p.s.i.

Example IX Approximately 170 grams of flucoke (Tidewater) was activated in a fluidized bed activation chamber in an atmosphere of normal atmospheric air at a bed temperature of approximately 550 C. for a period of 10 minutes. The activated flucoke was then extracted from the activation chamber and mixed with 30 grams of a low melting point asphalt and 2 grams of calcium oxide. The mixing was at a temperature in excess of C. and in a normal atmosphere. The admixed activated coke, binder and accelerator was briquetted at a compacting pressure of 1,000 p.s.i., followed by tempering and coking out as in the previous example. The resulting compacts had a crushing resistance in excess of 2,500 p.s.i.

Example X Approximately 90.5 grams of flucoke (Tidewater) was activated in a fluidized bed activation chamber in a normal air atmosphere at a temperature of between 500 C. to 550 C. for a period of approximately 10 minutes. The activated flucoke was then extracted from the activation chamber and mixed with 16 grams of the low melting point asphalt and 1.1 grams of calcium oxide at a temperature in excess of C. and in a normal atmosphere. The admixed activated coke, binder and accelerator was then tempered at a temperature of 225 C. for approximately 40 minutes. After tempering, the mixture was briquetted at a compacting pressure of 1,000 p.s.i. and was thereafter coked out at a temperature in the range of 600 C. to 920 C. for a period of approximately 21 minutes. The resulting compacts had an average crushing resistance in excess of 2,500 p.s.i.

Example XI Approximately 154.3 grams of flucoke (Tidewater) was activated in the fluidized activation chamber in an atmosphere of 20% atmospheric air and 80% steam at a bed temperature in the range of 650 C. to 700 C. for a period of 20 minutes. The activated flucoke was then extracted from the activation chamber and mixed with 27.2 grams of a low melting point coal tar (ring and ball 60 C.-65 C.) and 1.8 grams of calcium oxide as an accelerator at a temperature in excess of 120 C.

The admixed activated coke, binder and accelerator was compacted at 2,500 p.s.i. and then tempered under normal air atmosphere at a tempering temperature of approximately 225 C. for a period of 80 minutes. The compacts were then coked out at an end temperature of 920 C.

After cooling, the resulting compacts had an average crushing resistance of 7,500 p.s.i.

The real densities, in gms./cm. (i002) of the products of the foregoing examples are listed in the following table:

Table Example: Real density I 1.31 H 1.26 III 1.27 IV 1.30 V 1.20 VI 1.29 VII 1.30 VTII 1.28 IX 1.29 X 1.28 XI 1.30

What is claimed is:

1. A process for the preparation of a mixture of petroleum coke particles and an agglutinating carbonaceous binder comprising the steps of activating at least the exterior surfaces of said particles by heating said particles at a temperature of about 450 to 1,000" C. in an atmosphere selected from the group consisting of steam, air, and mixtures thereof, mixing such activated particles with about to 25% of said binder by weight of said particles, and tempering the resulting mixture at a temperature of about 200 to 300 C. in an atmosphere containing at least about 4% oxygen.

2. A process for the preparation of a compact of petroleum coke particles and an agglutinating carbonaceous binder comprising the steps of activating at least the exterior surfaces of said particles by heating said particles at a temperature of about 450 to 1,000 C. in an atmosphere selected from the group consisting of steam, air, and mixtures thereof, mixing such activated particles with about 10 to 25 of said binder by weight of said particles, and compacting and tempering the resulting mixture at a temperature of about 200 to 300 C. in an atmosphere containing at least about 4% oxygen.

3. A process for the preparation of a compact of petroleum coke particles and an agglutinating carbonaceous binder comprising the steps of activating at least the exterior surfaces of said particles by heating said particles at a temperature of about 450 to 1,000 C. in an atmosphere selected from the group consisting of steam, air, and mixtures thereof, mixing such activated particles with about 10 to 25% of said binder by weight of said particles, then compacting and tempering the resulting mixture at a temperature of about 200 to 300 C. in an atmosphere containing at least about 4% oxygen thereafter coking the tempered compact.

4. A process for the preparation of a compact of petroleum coke particles and an agglutinating carbonaceous binder comprising the steps of activating at least the exterior surfaces of said particles by heating said particles at a temperature of about 450 to 1,000 C. in an atmosphere selected from the group consisting of steam, air, and mixtures thereof, and for a period of about 5 minutes to 24 hours, mixing such activated particles with about 10 to 25 of said binder by weight of said particles, and compacting and tempering the resulting mixture at a temperature of about 200 to 300 C. in an atmosphere containing at least about 4% oxygen for a period of approximately to 2 hours.

5. A process according to claim 4 wherein about 0.5- 35% of an oxidizing accelerator based on the combined weights of said particles and binder is added tosaid mixture prior to tempering to reduce at least one of said tempering time and temperature.

6. A process according to claim 5 wherein said accelerator is an oxide selected from the group consisting of manganese dioxide, magnesium oxide, calcium oxide, and mixtures thereof.

7. A process for the preparation of a compact of pe troleum coke particles and an agglutinating carbonaceous binder comprising the steps of activating at least the exterior surfaces of said particles by heating said particles at a temperature of about 450 to 1,000 C. in an atmosphere selected from the group consisting of steam, air, and mixtures thereof, and for a period of about 5 minutes to 24 hours, mixing such activated particles with about 10 to 25 of said binder by weight of said particles, then compacting and tempering the resulting mixture at a temperature of about 200 to 300 C. in an atmosphere containing at least about 4% oxygen for a period of about A to 2 hours, and thereafter coking the tempered compact at a temperature of about 600 to 1,200 C.

8. A process according to claim 7 wherein the mixture is compacted at a pressure in the range of about 500 to 3,000 pounds per square inch.

9. As a new composition of matter, a tempered mixture of petroleum coke particles provided with activated exterior surfaces and about 10 to 25 of an agglutinating carbonaceous binder by weight of said particles.

10. A compacted tempered mixture of petroleum coke particles provided with activated exterior surfaces and about 10 to 25% of an agglutinating carbonaceous binder by weight of said particles, and having a crushing strength in excess of about 1,500 pounds per square inch.

11. A compacted, tempered and coked mixture of petroleum coke particles provided with activated exterior surfaces and about 10 to 25% of an agglutinating carbonaceous binder by weight of said particles, and having a crushing strength in excess of about 1,500 pounds per square inch and a real density of about 1.10 to 1.30 grams per cubic centimeter, said compacted, tempered and coked mixture being specially adapted for use in metallurgical and chemical processes.

References Cited UNITED STATES PATENTS 2,805,199 9/1957 Banes et a1 252502 2,835,605 5/1958 Nelson et al 252502 TOBIAS E. LEVOW, Primary Examiner. J. E. POER, Assistant Examiner. 

11. A COMPACTED, TEMPERED AND COKED MIXTURE OF PETROLEUM COKE PARTICLES PROVIDED WITH ACTIVATED EXTERIOR SURFACES AND ABOUT 10 TO 25% OF AN AGGLUTINATING CARBONEACEOUS BINDER BY WEIGHT OF SAID PARTICLES, AND HAVING A CRUSHING STRENGTH IN EXCESS OF ABOUT 1,500 POUNDS PER SQUARE INCH AND A REAL DENSITY OF ABOUT 1.10 TO 1.30 GRAMS PER CUBIC CENTIMETER, SAID COMPACTED, TEMPERED AND COKED MIXTURE BEING SPECIALLY ADAPTED FOR USE IN METALLURGICAL AND CHEMICAL PROCESSES. 